1. Field of the Invention
This invention relates to a tuning apparatus to be used for tuning musical instruments, particularly to a tuning apparatus which has a mounting member so as to be mounted on the musical instruments to be tuned.
2. Description of the Prior Art
As a tuning apparatus of the prior art Japanese Patent Laid-Open No. 164092/1987 to Seiko Instruments Inc., relates to a tuning apparatus which has a microphone for detecting a sound of a musical instruments to be tuned, as shown in FIG. 13. The sound produced by the musical instruments is inputted into a pickup, e.g., microphone, and converted into an electrical signal. The electrical signal is filtered by a filter 24 which has a band-pass width for passing each octave frequency. The signal provided by the filter 24 is processed by a pitch calculation circuit 3 through a waveform shaping circuit 2. The pitch calculation circuit 3 calculates an octave, a note and pitch deviation of the signal on the basis of a reference signal outputted from a reference signal generation circuit 4. The calculated results are displayed by a display 6 composed of an LED, liquid crystal display or the like. However, the conventional tuning apparatus picks up noise around the instrument to be tuned when the sound of the instrument is inputted to the microphone, and tuning is very difficult. In the case of inputting an electric signal outputted from a musical instrument to be tuned into the tuning apparatus through a cord coupling the musical instrument with the tuning apparatus, the cord is impedimental for a player and a noise induced on the cord makes tuning difficult.
In order to solve the above problems, another tuning apparatus having a built-in electromagnetic pickup such as that shown in FIG. 14 is also known. Although the above described problem is solved because the input signal is neither a sound nor an electric signal but an electromagnetic signal, the instruments being tuned are restricted to instruments using metal chords. In addition, an electromagnetic pickup 26 must be situated right above a chord 27 so as to sense the magnetic field and, as a result, tuning must be conducted while holding a tuning device 25 with one hand, thereby making tuning very troublesome.
Furthermore, in some musical instruments, a harmonic component such as a double wave and a triple wave produces a larger sound than a fundamental wave component. It is well known that when an amplitude of a double wave or a triple wave is larger than that of the fundamental wave, they are apt to be mistaken for the notes one octave higher and five degrees higher, respectively. To prevent this, it is necessary to insert the filter 2 as shown in FIG. 13, which makes the amplitude of the fundamental wave component larger than that of the harmonic component. However, since the tuning apparatus must have a plurality of filters for each octave, the scale of the circuit is enlarged. It is therefore impossible to obtain a small and inexpensive tuning appratus which is capable of exact detection of an octave.